Master cadre :-Spectroscopy

Spectroscopy may be defined s the interaction of matter with electromagnetic radiations so that energy is absorbed or a method in accordance with relation
             ΔE=hν
There is two types of spectroscopy
(1) emission spectroscopy
(2) absorption spectroscopy
Emission spectroscopy
  • Atoms or molecules are subjected to to intense heat are an electric discharge ,absorb energy and get excited.
  • But lifetimes of excited state is very short
  • So they return to their lower exited states or ground states.
  • And at that time absorbed energy is is released in the the form of of light.
  • And this light passed through prism it gives rise to emission spectrum
  • Such a recorded spectrum on photographic plate appears as bright lines on dark background.
  • Emission spectroscopy is used for study of atoms.

Absorption spectroscopy
  • If electromagnetic radiations allowed to pass through medium some of it reflected some is observed and other is transmitted
  • when this transmitted light is passed through prism are great and an absorption spectrum is obtained.
  • this spectrum is indicates those portion of incident light that have been absorbed by the medium.
  • Absorption spectroscopy is used for determination of structure of organic compound.
Q1. Emission spectroscopy is not related to
(a) produced when atoms release energy
(b) comprise of coloured lines in the spectrum
(c) helpful in figuring out the composition of certain matter
(d) comprise of dark lines or gaps in the spectrum
Ans(d)
Q2. Which of the following is true
(a)absorption spectroscopy is used to figure out the ability of certain objects to retain heat it and its absorption level
(b) emission spectroscopy produced when atoms absorb energy
(c) lifetime of atoms or molecules in excited state is long
(d) none of these
Ans(a)

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